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A. The patient must have been exposed to a stressful event or situation (either short- or long-lasting) of exceptionally threatening or catastrophic nature, which would be likely to cause pervasive stress in almost anyone.

B. There must be persistent remembering or "reliving" of the stressor in intrusive "flashbacks", vivid memories, or recurring dreams, or in experiencing distress when exposed to circumstances resembling or associated with the stressor.

C. The patient must exhibit an actual or preferred avoidance of circumstances resembling or associated with the stressor, which was not present before exposure to the stressor.

D. Either of the following must be present:

1. inability to recall, either partially or completely, some important aspects of the period of exposure to the stressor;

2. persistent symptoms of increased psychological sensitivity and arousal (not present before exposure to the stressor), shown by any two of the following:

(a) difficulty in falling or staying asleep;

(b) irritability or outbursts of anger;

(c) difficulty in concentrating;

(d) hypervigilance;

(e) exaggerated startle response

E. Criteria B, C, and D must all be met within 6 months of the stressful event or of the end of the period of stress. (For some purposes, onset delayed more than 6 months may be included, but this should be clearly specified.)

Post-traumatic stress disorder (PTSD) is a syndrome that develops following exposure to an extremely threatening or horrific event or series of events that is characterized by all of the following:

1) re-experiencing the traumatic event or events in the present in the form of vivid intrusive memories, flashbacks, or nightmares, which are typically accompanied by strong and overwhelming emotions such as fear or horror and strong physical sensations, or feelings of being overwhelmed or immersed in the same intense emotions that were experienced during the traumatic event;

2) avoidance of thoughts and memories of the event or events, or avoidance of activities, situations, or people reminiscent of the event or events

3) persistent perceptions of heightened current threat, for example as indicated by hypervigilance or an enhanced startle reaction to stimuli such as unexpected noises.

The symptoms must persist for at least several weeks and cause significant impairment in personal, family, social, educational, occupational or other important areas of functioning.

Additionally, ICD 11 includes a category called "Complex post-traumatic stress disorder," which is described as:

A disorder that may develop following exposure to an event or series of events of an extremely threatening or horrific nature, most commonly prolonged or repetitive events from which escape is difficult or impossible (e.g., torture, slavery, genocide campaigns, prolonged domestic violence, repeated childhood sexual or physical abuse).

The disorder is characterized by the core symptoms of PTSD; that is, all diagnostic requirements for PTSD have been met at some point during the course of the disorder.

In addition, Complex PTSD is characterized by:

1) severe and pervasive problems in affect regulation;

2) persistent beliefs about oneself as diminished, defeated or worthless, accompanied by deep and pervasive feelings of shame, guilt or failure related to the traumatic event

3) persistent difficulties in sustaining relationships and in feeling close to others. The disturbance causes significant impairment in personal, family, social, educational, occupational or other important areas of functioning.

Diagnostic thresholds have been lowered for children and adolescents to account for development.

Separate and additional criteria have been added for children age 6 or younger.

Child sexual abuse has been found to have a substantial effect on the development of PTSD.[1]

Children with higher exposure to trauma, less social support, and other major life events are more likely to have continued PTSD symptoms 7 months after a trauma.[2] 10 months after a trauma, however, only experience of a major life event remained predictive of continuing PTSD symptoms.[2]

Lack of social support, specifically lack of support by a teacher, was predictive of higher PTSD symptoms among children who had gone through an environmental trauma.[2]

Children who reported using blame and anger as strategies for coping had higher levels of PTSD symptoms 10 months after a trauma.[2]

Negative affect in children before a traumatic event was predictive of development of PTSD symptoms after a traumatic event.[3]

Posttraumatic stress disorder is now more sensitive to development in that diagnostic thresholds have been lowered for children and adolescents. Furthermore, separate and additional criteria have been added for children age 6 years of age or younger.

Base rates of PTSD in different clinical settings and populations[edit]

This section describes the demographic settings of the populations sampled, base rates of PTSD diagnoses, country/region sampled, and the diagnostic methods that were used. Using this information, clinicians will be able to anchor the most appropriate rate of PTSD that they are likely to see in their clinical practice.

♦ Note: These rates were using broad PTSD Checklist scoring criteria of being scored positive if subjects reported at least one intrusion symptom, three avoidance symptoms, and two hyperarousal symptom that were categorized as at the moderate level. The 11.5% is for soldiers returning from deployment in Iraq, 19.5% is for soldiers returning from Afghanistan. Another common practice is to use a strict cutoff of 50 on the PCL, above which someone screens positive for PTSD. With this cutoff, rates are 6.2% and 12.9% for Service Members returned from Afghanistan and Iraqi, respectively.

The following section contains a brief overview of treatment options for PTSD and list of process and outcome measures for PTSD. The section includes benchmarks based on published norms for several outcome and severity measures, as well as information about commonly used process measures. Process and outcome measures are used as part of the process phase of assessment. For more information of differences between process and outcome measures, see the page on the process phase of assessment.